Fouled Wideband sensor?

Ok, let's say someone who didn't know that my car hadn't been tuned yet drove it. For like 80 miles. It must have run extremely rich, through the whole band, like 12:1 or so.

So now I'm tuning it, and the wideband doesn't seem to respond at all. At idle it reads accurately, but anywhere else, I get around 12.45:1. I pulled it, and it was covered in carbon deposits, thick, fluffy, velvety carbon. I wiped it off, being careful not to get it inside, but I'm still not getting a very good response at anything above about 1200 rpm. Could it have been fouled inside, and thus screwed up pretty bad?

Is it possible to fix it, or should I order one now, and wait another two weeks without a decent car to drive?